In high capacity cellular mobile radiotelephone systems, a plurality of base stations, also referred to as cell sites, are arranged so that each cell site covers a respective geographical area called a cell. Typically, each such cell site contains a radio transmitter-receiver and is directly wired to a mobile telephone switching office (MTSO) which in turn is part of a regional or nationwide network of telephone switching offices. One example of such cell site is the AT&T Series I cell sites (Model 1 and Model 2 architecture) used in the family of AUTOPLEX.RTM. cellular telecommunications systems which are commercially available from the American Telephone and Telegraph Company of New York, N.Y. Such known cell sites have operated satisfactorily for their intended purposes for which they were originally designed. However, because of increased demands for more radio channels occupying smaller physical facilities in combination with requirements of integrating digital data links and facilities in the radio frames at the site, there exists a need for a digital cell site capable of handling analog as well as digital radio channel units while exhibiting greater capacity, easier maintenance and upgrade, and more flexibility than now exist with commercially available equipments.